You ate something hours ago, maybe undercooked chicken, a suspect salad, or leftovers that sat out too long. Now you’re doubled over with cramps, racing to the bathroom, wondering if this is food poisoning or something worse.
Foodborne illness affects approximately 48 million Americans each year; that’s 1 in 6 people¹. While most cases resolve within a few days, some require emergency care to prevent life-threatening dehydration, organ damage, or complications in high-risk individuals.
This guide explains what foodborne illness is, the pathogens that cause it, how to recognize food poisoning symptoms, which cases need the ER, and how to protect yourself through proper food safety.
What Is Foodborne Illness?
Foodborne illness, commonly called food poisoning, is any illness caused by eating or drinking contaminated food or beverages. Contamination can come from bacteria (like Salmonella or E. coli), viruses (like norovirus), parasites (like Toxoplasma), or toxins produced by microorganisms.
Symptoms of foodborne illness include vomiting, diarrhea, abdominal cramps, and fever, with onset ranging from 30 minutes to several weeks after consuming contaminated food.
The FDA estimates foodborne illness causes 128,000 hospitalizations and 3,000 deaths annually in the United States. Most cases are preventable through proper food handling, cooking, and storage.
Foodborne Illness Causes
Food becomes contaminated at any point from farm to table; during growing, harvesting, processing, storing, shipping, or preparing. The three main categories of contaminants are:
Bacteria
Bacteria are the most common cause of foodborne illness. They multiply rapidly in the “danger zone” between 40°F and 140°F, doubling in number every 20 minutes under ideal conditions. Common bacterial culprits include Salmonella, E. coli, Listeria, Campylobacter, and Clostridium perfringens.
Viruses
Norovirus is the leading cause of foodborne illness outbreaks, responsible for 58% of cases in the US annually. Unlike bacteria, viruses don’t multiply in food; they use food as a vehicle to reach your digestive system. Hepatitis A is another virus transmitted through contaminated food or water.
Parasites
Parasites like Toxoplasma gondii, Cyclospora, and Cryptosporidium can contaminate food and water. Parasitic infections are less common but can cause prolonged illness, particularly in immunocompromised individuals.
How Food Becomes Contaminated
- Cross-contamination: Raw meat juices contact ready-to-eat foods. Using the same cutting board for raw chicken and salad vegetables is a common example.
- Improper cooking: Meat, poultry, or eggs not reaching safe internal temperatures allow pathogens to survive.
- Temperature abuse: Perishable food left in the danger zone (40-140°F) for more than two hours—or one hour above 90°F.
- Infected food handlers: Workers who don’t wash hands after using the bathroom or while symptomatic spread pathogens to food.
- Contaminated water or soil: Produce irrigated with contaminated water or grown in contaminated soil can carry pathogens.
Common Foodborne Pathogens: Symptoms and Timelines
Different pathogens produce different symptoms and timelines. Knowing the pattern can help identify the likely cause.
| Pathogen | Onset Time | Key Symptoms | Common Sources |
| Norovirus | 12-48 hours | Vomiting, watery diarrhea, cramps | Leafy greens, shellfish, any food touched by infected handler |
| Salmonella | 6-72 hours | Diarrhea, fever, abdominal cramps | Raw/undercooked eggs, poultry, meat, unpasteurized milk |
| E. coli (STEC) | 1-10 days | Severe cramps, bloody diarrhea, vomiting | Undercooked beef, raw milk, contaminated produce (leafy greens) |
| Listeria | 1-4 weeks | Fever, muscle aches, confusion; can cause miscarriage | Deli meats, soft cheeses, unpasteurized dairy, smoked seafood |
| Campylobacter | 2-5 days | Diarrhea (often bloody), cramps, fever | Raw/undercooked poultry, unpasteurized milk, contaminated water |
| Staph aureus | 30 min – 6 hours | Sudden severe nausea, vomiting, cramps | Foods left at room temperature (salads, cream-filled pastries) |
| Botulism | 18-36 hours | Double vision, drooping eyelids, slurred speech, paralysis | Foods left at room temperature (salads, cream-filled pastries) |
Food Poisoning Symptoms
Food poisoning symptoms vary depending on the pathogen, but most cases share common signs that develop within hours to days after eating contaminated food.
Common Food Poisoning Symptoms
- Nausea and vomiting: Often the first sign, especially with toxin-producing bacteria like Staph. May be projectile with norovirus.
- Diarrhea: Watery or bloody depending on the pathogen. Bloody diarrhea suggests E. coli, Campylobacter, or Shigella.
- Abdominal cramps: Ranging from mild discomfort to severe pain.
- Fever: Indicates your immune system is fighting infection. High fever (over 101.5°F) warrants medical attention.
- Fatigue and weakness: Result from fluid loss and the body’s immune response.
Severe Symptoms Requiring Immediate Care
- Bloody vomit or stool: Indicates potential internal bleeding or severe infection.
- Signs of severe dehydration: Extreme thirst, dark urine, dizziness, confusion, or no urination for 8+ hours.
- Neurological symptoms: Blurred or double vision, difficulty swallowing, muscle weakness, or tingling—may indicate botulism.
- High fever: Temperature above 101.5°F (38.6°C) that doesn’t respond to fever reducers.
Who Is at Higher Risk for Severe Foodborne Illness?
While anyone can get food poisoning, certain groups face higher risk of severe illness, hospitalization, and death:
- Adults 65 and older: Weakened immune response and reduced stomach acid make older adults more susceptible to severe infection.
- Children under 5: Immature immune systems and smaller body size mean dehydration develops faster.
- Pregnant women: Listeria infection can cause miscarriage, stillbirth, or life-threatening infection in newborns, even when the mother has mild symptoms.
- Immunocompromised individuals: People with HIV/AIDS, cancer patients on chemotherapy, organ transplant recipients, and those on immunosuppressive medications.
- People with chronic conditions: Diabetes, kidney disease, and liver disease increase vulnerability to complications.
When to Go to the ER for Food Poisoning
Most food poisoning resolves within 1-3 days with rest and fluids. However, certain symptoms signal a medical emergency.
Seek Emergency Care for Food Poisoning If You Experience:
- Blood in vomit or stool
- Diarrhea lasting more than 3 days
- Inability to keep any liquids down for 24 hours
- Signs of severe dehydration (extreme thirst, dizziness, dark urine, confusion, fainting)
- Fever above 101.5°F (38.6°C) that won’t come down
- Severe abdominal pain that doesn’t improve after a bowel movement
- Neurological symptoms: blurred vision, muscle weakness, tingling, difficulty speaking or swallowing.
Pregnant women, adults over 65, children under 5, and anyone with a weakened immune system should seek medical evaluation earlier, before severe symptoms develop. For infants and young children, even moderate dehydration is dangerous.
What to Expect at the ER
Emergency treatment for food poisoning may include IV fluids to correct dehydration and electrolyte imbalances, anti-nausea medication to stop vomiting, stool or blood tests to identify the pathogen, antibiotics if bacterial infection is confirmed (not effective for viral causes), and monitoring for complications like kidney damage from E. coli or respiratory failure from botulism.
Treating Mild Food Poisoning at Home
If symptoms are mild and you’re not in a high-risk group, you can usually recover at home with these tips:
- Stay hydrated: Sip water, clear broths, or oral rehydration solutions (like Pedialyte). Avoid caffeine and alcohol, which worsen dehydration.
- Rest your stomach: Avoid solid food until vomiting stops. When ready, start with bland foods: bananas, rice, applesauce, toast (the BRAT diet).
- Avoid dairy and fatty foods: These are harder to digest and can worsen symptoms.
- Don’t take anti-diarrheal medications immediately: Diarrhea helps expel the pathogen. Consult a doctor before using medications like loperamide, especially if you have bloody diarrhea or fever.
- Monitor your symptoms: If symptoms worsen or don’t improve within 2-3 days, seek medical care.
Food Safety Tips to Prevent Foodborne Illness
Most foodborne illness is preventable. Follow these food safety principles:
Clean
Wash hands with soap and water for 20 seconds before and after handling food, after using the bathroom, and after touching pets. Wash cutting boards, utensils, and countertops with hot soapy water after preparing each food item. Rinse fresh produce under running water, even if you plan to peel it.
Separate
Keep raw meat, poultry, seafood, and eggs away from ready-to-eat foods in your shopping cart, refrigerator, and during preparation. Use separate cutting boards for raw meat and produce. Never place cooked food on a plate that held raw meat.
Cook
Use a food thermometer; color alone doesn’t indicate safety. Cook to these minimum internal temperatures: 165°F for poultry, 160°F for ground meats, 145°F for whole cuts of beef, pork, lamb, and fish. Reheat leftovers to 165°F.
Chill
Refrigerate perishable foods within 2 hours (1 hour if above 90°F). Keep your refrigerator at 40°F or below. Thaw frozen food in the refrigerator, cold water, or microwave; never on the counter. Don’t leave leftovers in the “danger zone” (40-140°F).
Final Thoughts
Foodborne illness ranges from a miserable few days to a life-threatening emergency. Recognizing symptoms early, understanding when to seek care, and following food safety practices can protect you and your family.
If you’re experiencing severe food poisoning symptoms, such as bloody stool, signs of dehydration, high fever, or neurological changes, don’t wait. ER of Fort Worth is open 24/7 with IV hydration, diagnostic testing, and emergency treatment available immediately.
FAQs About Foodborne Illness
1. How long does food poisoning last?
Most food poisoning cases resolve within 1-3 days. Some infections (like Campylobacter or parasites) may last a week or longer. Symptoms persisting beyond 3 days warrant medical evaluation.
2. How soon after eating bad food do symptoms start?
It varies by pathogen. Staph toxins cause symptoms within 30 minutes to 6 hours. Salmonella typically takes 6-72 hours. Listeria can take 1-4 weeks. The food that made you sick isn’t always the last thing you ate.
3. Can you have food poisoning without vomiting?
Yes. Some pathogens cause primarily diarrhea with little or no vomiting. Campylobacter and E. coli often cause bloody diarrhea and cramps without significant vomiting.
4. Is food poisoning contagious?
Some types are. Norovirus is highly contagious and spreads through contact with infected people, contaminated surfaces, or food handled by infected individuals. Bacterial infections like Salmonella typically aren’t spread person-to-person but can be if hygiene is poor.
5. Should I go to the ER or urgent care for food poisoning?
Go to the ER for severe symptoms: bloody stool, signs of severe dehydration, high fever, inability to keep fluids down, or neurological symptoms. Urgent care can handle milder cases but cannot provide emergency intervention.
6. Do antibiotics treat food poisoning?
Only bacterial food poisoning responds to antibiotics, and not all cases require them. Viral infections (like norovirus) don’t respond to antibiotics. In some cases, antibiotics can worsen outcomes (as with certain E. coli infections). Your doctor will determine if antibiotics are appropriate based on the pathogen involved.
